1. Field of the Invention
The present invention relates generally to conveying devices, and more specifically to conveying devices having a universal joint connecting individual conveying elements that may be extended from and retracted into the conveying device, and particularly to hollow universal joints for use with retractable conveyor elements of an aircraft baggage loader.
2. Background Information
Baggage loading devices are common. A typical device includes a vehicle equipped with an endless belt upon which luggage or other items are placed. Movement of the belt conveys the luggage from one end of the vehicle to the other end. An airplane loading vehicle preferably elevates at an angle so the luggage is transported from a lower level and into higher positioned cargo area of the airplane. In some instances add-on conveyors are included with the main belt-driven loader.
One example of such an add-on conveyor is found in U.S. Pat. No. 5,584,376 to Voldby. The add-on conveyor in Voldby is generally positioned in a retracted state beneath the main belt loader of the apparatus. The conveyor may be extended into the cargo compartment of the aircraft. A user manually pushes the conveyor into position while an assistant in the cargo compartment guides the end of the conveyor. The conveyor can be withdrawn progressively by manually pulling the conveyor from the outside in the opposite direction. At least a certain number of the rollers of the conveyor may include driving means to power the rollers which in turn convey baggage or other items. The conveyor includes a flexible driving means, such as a cardan chain, which has two degrees of freedom, one along the curve and the other up/down in relation to a horizontal plane. Examples of such chain include the type “Uni-slat top” or “Uni-Flex”, both from the firm Uni-Chains Int. A/S Vejle, Denmark. A chain of the latter type essentially consist of Y-shaped chained links, linked together so that the chain can be curved like a bike chain, but can also be bent sidewards in a curve. The slat-variety includes elements with a slat of flattened surface that are linked together and have similar movement as a Y-shaped variety. Neither include a hollow opening disposed for running of cables within the chain-like structure.
Another example of a conveyor device is found in PCT Application Publication No. WO 2005/073110 A1 entitled Conveying Device, by Martin Vestergaard, published Aug. 11, 2005. The conveyor device in that application includes a variety of mechanisms for articulation of respective conveying elements. The device also includes an embodiment where the conveying device of that invention is arranged underneath the device for transporting the luggage from the cargo hold to the luggage trolley placed on the ground. This is done by arranging a box-like structure underneath the conveyor such that the conveying device according to that disclosure can slide out of and into that box-like structure. For that purpose, a guide rail is arranged inside the box such that the chain box elements 4 of the conveying device according to that disclosure may by means of guidance rollers roll inside the guide rail such that it is relatively easy to eject or insert the conveying device into the conveyor. While the device of Vestergaard shows a hollow chain box 4 as indicated in prior art FIG. 15 by reference number 43 for placing different means for powering the rollers, wires etc. (which FIG. 15 generally corresponds to FIG. 15 of the Vestergaard PCT application), such particular structure of FIG. 15 or disclosure does not show a universal joint for articulation to achieve two degrees of freedom.
Another example of a conveyor device in use outside the United States and generally demonstrated at www.powerstow.com includes a retractable conveyor having multiple rollers. This device is marketed by Power Stow A/S of Denmark under the name Rollertrack. There is no disclosure of the conveyor units having a yoke for articulation to achieve two degrees of freedom or to swivel about two axes.
Other examples of conveyor devices having a retractable conveyor are found in U.S. patent application Ser. No. 10/169,361 to Thogersen, publication No. US 2003/0091415, and U.S. patent application Ser. No. 10/720,471, publication No. US 2004/0105740. These applications show a retractable conveyor constructed for storing in a generally folded configuration. The retractable conveyor units include an endless belt. In one embodiment, the moving of the conveyor units to and from the cargo compartment of an aircraft is carried out by means of a driving, endless conveyor belt which cooperates with the bottom side of the conveyor units, such as by way of friction; or the conveyor part is pushed and moved into the cargo compartment; or the invention is generally silent as to the particulars of how the conveyor units are driven or retracted or extended. The pivoting of respective conveyor units in two degrees of freedom requires a complicated design and accommodates pivoting in limited direction. For instance, the individual conveyor units pivot in a bottom-to-bottom relationship but do not freely pivot in a top-to-top relationship (i.e., they fold downward (bottom-to-bottom) with respect to each other but there is no showing that they fold top-to-top, or upward with respect to each other).
The present invention, however, provides a novel conveying device and advantages over prior designs. The device includes a hollow universal articulating joint for increased performance. Numerous other advantages and novel features of the present invention are disclosed.